Turbine valve stems and associated turbine valve bypass discs employed in connection with steam power generation systems suffer from erosion due to iron oxide particles such as magnetite particles entrained in the steam passing through the valves. The steam can have a temperature of up to 1000 F, pressure of up to 2500 psig, and be traveling at a rate of up to 3000 ft/second. Heretofore, these valve stems have been constructed of low alloy steels with a wear-resistant coating thereon. The low alloy steels have had adequate strength at the required service temperatures of 1000 F.